https://www.allaboutbirds.org/guide/W...

Mature males are large mostly dark sea duck with bulge at base of orange-red bill. White in wings is often visible at rest. White comma-shaped patch (or "Viking horn") around eye.

Females are large brownish sea duck with large, sloping dark bill. Two white facial patches, both relatively round. White wing patch often visible at rest.

White-winged Scoters are usually the scarcest of the three scoter species in North America, but scanning through such flocks will usually turn up a larger bird with telltale white patches on the inner wing (very noticeable in flight and often partly visible on resting birds). During migration, after heavy storms, or when the Great Lakes have frozen over, they often show up on inland lakes.


White-winged Scoters breed in the boreal forest, usually not far from lakes and ponds surrounded by shrubs, and much less often in tundra. These remote lakes are usually 125 acres in extent or larger and surrounded by species of raspberry, gooseberry, snowberry, rose, nettle, or reed. Many of the lakes have sandy bottoms. The brushy areas around the lakes are ideal for concealing the nest, which is sometimes 300 feet or so from the lakeshore. After breeding, some White-winged Scoters remain to molt on the nesting lake, while others uses larger lakes, rivers, or even open saltwater habitats. In winter, some White-winged Scoters remain inland, especially on the Great Lakes, but most move to Atlantic and Pacific coastal areas, where they use relatively shallow areas with sandy or stony bottoms.